This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Polymorphic alleles in genes that regulate fat accumulation within adipocytes and hepatocytes are associated with susceptibility to nonalcoholic fatty liver disease (NAFLD) in children. Specific Aims: 1. To collect parental DNA for all pediatric participants in the NIH Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN). 2. To genotype children with NAFLD and their parents in key biological pathways believed to be relevant to the development of NAFLD.